Domestic dryer speed control



y 1970 N. J.- BULLOCK ET 1... 3,509, 40

DOMESTIC DRYER SPEED CONTROL Filed Sept. 5, 1968 v 2 Sheets-Sheet 1 I NVEN TORS 102mm [fizz/0&5

7516: De v13 Q1 4 W ATTORNEY May 5, 1970 N. J. BULLOCK ET AL 3,509,640

DOMESTIC DRYER SPEED CONTROL Filed Sept. 5, 1968 2 Sheets-Sheet 2ATTORNEY United States Patent 3,509,640 DOMESTIC DRYER SPEED CONTROLNorman J. Bullock and Ted C. Davis, Dayton, Ohio, assignors to GeneralMotors Corporation, Detroit, Mich., a corporation of Delaware FiledSept. 3, 1968, Ser. No. 756,915 Int. 'Cl. F26b 11/02 US. Cl. 34133 3Claims ABSTRACT OF THE DISCLOSURE In preferred form, a domestic dryerapparatus having an outer cabinet surrounding a tumbling drum mountedfor rotation on a horizontal axis. An air heating and distributionsystem directs heated air through the tumbling drum during normal dryingwherein the drum is rotated by a belt pulley system. During a no-tumbledrying period a drive motor is maintained energized to operate the airblower of the heating system. A belt directed over a drive motor sheaveand a periphery of the drum is held away from the drive sheave by anextension on an idler pulley position compensating lever which isshifted to a belt unloading position during no-tumble operation by meansincluding an operator located in the door well of the dryer.

This invention is directed to domestic dryer apparatus and moreparticularly to domestic dryer apparatus having a no-tumble phase ofoperation wherein the dryer drum is maintained stationary while a heatedair stream is directed through its interior for drying articles therein.

In dryer apparatus of the type having a tumbling drum mounted forrotation about a horizontal axis one suitable drum drive system has beenof the type including a single drive belt which is passed over the outerperiphery of the drum and a drive sheave to operate the drum duringenergization of an electric drive motor.

One advantage of a system of this type is that the drive motor is ableto concurrently operate a blower motor for circulating heated air acrossarticles in the tumbling drum during a drying phase of operation. Afurther advantage of a drive system of this type is that it can becontinually adjusted during its operation by the inclusion of a low costidler pulley between the drum periphery and a motor drive sheave tocontinually compensate for belt slack that occurs during operation.

One system of this type includes a pivot arm and a tension spring forbiasing the pivot arm in a direction to move an idler pulley carried onthe arm upwardly and against a single belt drive at a point between theperiphery of the drum and the drive sheave to tension the belt therebyto produce good driving engagement between drive sheave and drum duringmotor operation.

Such a system gives a good, low cost, positive drive of a tumbling drumdriven on a horizontal axis and assures that articles within the drumwill fall through the interior of the drum in a free falling patternthrough which a force draft, heated air stream may be passed for quicklyremoving moisture from the tumbled articles.

It is also recognized in drying apparatus that at times, certainarticles might better be dried by locating the articles within the druminterior and allowing the heated, forced draft air stream to passthrough the tumbling drum without the articles being tumbled wtihin thedrum.

Accordingly, an object of the present invention is to improve theoperation of dryer apparatus having a horizontal tumbling drum driven bya drive system including a motor and a single, continuous belt passedover the drive sheave of the motor and the periphery of the drum andwherein the same motor is utilized to operate a blower for distributingheated air through the drum interior during drying operation by theprovision of means to release the drive belt tension during a no-tumblephase of dryer operation wherein the drive motor continues to operatethe blower to direct heated air through the drum interior and whereinthe means for removing tension from the single drive belt also includesmeans for positioning the single drive belt out of frictional engagementwith the drive sheave of the motor thereby to reduce belt wear duringthe no-tu'mble operation.

A further object of the present invention is to provide a domestic dryerapparatus having a tumble phase of operation and a no-tumble phase ofoperation wherein a single drive motor concurrently operates a beltpulley system for rotating a horizontal tumbling drum while driving ablower motor to circulate heated air through the interior of the drum;no tumbling action occurring in the drum by removing tension from thebelt drive by means that concurrently locates the belt drive completelyout of frictional engagement with the drive sheave to prevent excessivefrictional wear of the single belt drive during notumble operation.

In one working embodiment the above-stated objects of the presentinvention are attained in a domestic dryer apparatus of the typeincluding a tumbling drum rotated about a horizontal axis. A single beltmember is directed over the periphery of the dryer drum and a drivesheave on a motor that concurrently operates a blower for directingheated air through the tumbling drum. An idler pulley located betweenthe drum periphery and the drive sheave is supported on a pivot arm thatis connected to a tension spring that biases the idler pulley againstthe drive belt to maintain it under tension during a tumble phase ofoperation. The system includes a push-pull operator having a handlelocated in the door well of the dryer and which is positionable to ano-tumble control position wherein a wire component of the push-pulloperator is connected to the idler pulley pivot arm to back the idlerpulley away from the belt to release drive belt tension and thereby stopdrum rotation. The means for connecting the push-pull operator to thepivot arm includes a guard extension that concurrently acts on the beltat a point between the idler pulley and thedrive sheave to shift thebelt completely out of driving or frictional engagement with the drivesheave to prevent Wear of the belt during no-tumble operation. Thepush-pull operator has a tumble position wherein the wire component ismoved out of coupled engagement with the arm extension and positioned toenable the pivot arm to freely move in response to the force of thetension spring against the belt to drivingly couple the sheave to thedrum and to concurrently allow the arm extension to move along with thepivot arm free of the wire to enable the tension spring to shift theidler pulley to continually compensate for belt slack during operationof the dryer.

The foregoing and other objects and advantages of the invention willbecome apparent from the following description and the accompanyingdrawings, in which:

FIGURE 1 is a view in perspective of a dryer cabinet having portionsthereof broken away to show a belt pulley drive system and manualOperator for conditioning the drive system for a no-tumble phase ofdrying operation;

FIGURE 2 is an enlarged front elevation view of an operating handle inthe inventive system;

FIGURE 3 is an enlarged fragmentary end elevational view of the drivebelt and pulley arrangement in the present invention;

FIGURE 4 is a fragmentary end elevational view of the arrangement inFIGURE 3 showing the location of parts of the drive system during ano-tumble phase of drying;

FIGURE 5 is a schematic view of the dryer in FIG- URE 1 showing an aircirculation system in the dryer;

FIGURE 6 is a schematic outline drawing of the drive belt path betweenthe tumbling drum of the dryer and its operating motor;

FIGURE 7 is a view like FIGURE 3 showing the operativepositions of thebelt drive system following belt slack takeup;

FIGURE 8 is a view in vertical section taken along the line 8-8 ofFIGURE 3 looking in the direction of the arrows; and

FIGURE 9 is a view in vertical section taken along the line 9-9 ofFIGURE 4 looking in the direction of the arrows.

Referring now to the drawings, in FIGURE 1 a domestic' laundry dryer 10is illustrated of the type including an'outer cabinet 12 having a top14, a front 16, spaced apart side walls 18 and 20 connected to the topand front to form an enclosed machinery compartment or space 22, accessto which is provided by a rear wall panel 24.

In the illustrated arrangement the front 16 has a door well 26 formedtherein formed around an access opening 28 into the interior 30 oftumbling drum 32.

As generally shown in FIGURE 5, the tumbling drum 32 is supported at itsrear and front walls by means that support the drum 32 for rotationabout a horizontal axis.

In accordance with certain principles of the present invention the drum32 is operated by an improved belt pulley drive system 34 including anelectrically energized drive motor 36 supported on a saddle support 38fixedly secured to a base framework 40 within the outer cabinet 12 atthe bottom thereof.

The drive motor includes a first drive shaft 42 on one end thereof whichhas a drive sheave 44 fixedly secured thereto.

An upstanding L-shaped bracket 46 has its short leg fixedly secured bysuitable fastening means representatively shown as screws 48 to one endof the saddle support 38. The bracket is inclined to one side of thesaddle support 38 and has its uppermost end 50 located slightly belowthe outer periphery of the tumbling drum 32. A pivot pin 52 is directedthrough the uppermost end 50 and to the fulcrum of a bellcrankcompensating member 54. The heads of the pin 52 are formed to receivesnap rings that positively interconnect these elements while retaining adesired freedom of pivotal movement therebetween about the pivot pointdefined by the pin 52.

The bellcrank member 54 includes a first arm 56 depending downwardly ofits supported fulcrum point and to one side of the upstanding L-shapedbracket 46 Where it is connected to one end of a tension spring 58having its opposite end connected to a tab 60, integral with andextending outwardly of the front face of the bracket 46.

A second arm 62 on the member 54 is inclined downwardly of its fulcrumin the general direction of the axis of rotation of the shaft 42; Asupport pin 64 is carried on the arm 62 as best seen in FIGURES 8 and 9.

An idler pulley 66 on the support pin 64 is located away from the secondarm 62 by a spacer element 68, and a washer 70 and snap ring 72 fit overthe end of the pin 64 to hold the idler pulley 66 thereon for relativerotation with respect thereto.

The arms 56 and 62 of the bell crank compensating member 54 areconfigured to cause the idler pulley to be pivoted about the fulcrum ofthe member 54 along an arcuate path 74 to cause the upper surface of theidler pulley 66 to continually press upwardly against a reach 76 of acontinuously formed single poly-V drive belt 78 located between thelowermost part of the outer periphery of the tumbling drum 32 and thedrive sheave 44.

The idler pulley 66 thereby serves to maintain the belt 78 in tensionthrough a path extending from the upper surface of the idler pulley 66,thence to the underside of the drum 32 and about its outer periphery, asbest seen in FIGURE 6, thence to return from the drum and wrapapproximately 180 around the underside of the drive sheave 44 back tothe idler pulley 66.

The arcuate path 74 defines the movement of the idler pulley center asit moved by the tension spring 58 to compensate for the slack in thesingle poly-V drive belt which occurs during normal dryer operation.

The path is upwardly and away from the center line of the drive shaft 42and, accordingly, there is no tendency for the drive belt to be pinchedaround the sheave 44 to an extent that might prevent undesirablefrictional wear of the belt.

In accordance with certain principles of the present invention thesingle drive motor 36 has a second drive shaft 80 which is connected toa recirculating blower 82 in an air circulation system shown in FIGURE 5as including an inlet 84 in the rear panel of the dryer. The system alsoincludes an exhaust port 86 in the panel. The recirculating blower 82has the outlet thereof connected to a conduit 88 for directing air fromthe blower through the exhaust port to initiate an air flow pattern fromthe air inlet 84 thence across a heat source representatively shown asan electrical resistance element 90. Heated air is directed through aplurality of apertures 92 in the rear wall of the tumbling drum 32 andis drawn through the interior 30 of the tumbling drum, thence throughthe access opening 28 and into exhaust ports 94 formed around the doorwell 26. The exhaust ports 94 communicate with a duct 96 whichcommunicates with the intake of the recirculating blower 82.

During normal operation a controller 98 on a rearwardly located upperpanel of the cabinet 12 is positioned to condition electrical circuitmeans (not shown) for controlling the energization of the resistanceelement and the drive motor 36 to concurrently produce a force draft airpattern within the interior of the tumbling drum and a heat inputsufiicient to remove moisture from articles being tumbled through thedrum during a tumble phase of dryer operation.

Additionally, the illustrated system includes means for conditioning thedrive system to produce a no-tumble phase of operation wherein thecontroller 98 is set in a normal operating position to concurrentlyenergize the resistance element 90 and the drive motor while the beltpulley drive system 34 is manually operated to prevent drum rotation.

Such no-tumble operation has an advantage in that delicate lingerie, andother articles can be placed within the interior of the tumbling drum ina location where the air pattern therein will convectively dry thearticles and yet the drum is maintained stationary so that the articlesbeing dried are not subjected to frictional engagement with the interiorsurface of the drum and distributing vanes normally found therein.

Thus, in accordance with certain principles of the present invention theabove-described belt pulley drive system 34 is associated with amanually operated controller 102 that includes an operating arm 104located in the recessed door well 26 of the outer cabinet 12 and apush-pull operator 106 for connecting the arm 104 to a belt guard andrelease extension 108 on the lower end of the arm 62.

More particularly and as is best seen in FIGURES l and 2, the operatingarm 104 includes a fiat handle portion 110 in the well 26 which isconnected to a shaft 112 extending interiorly of the outer cabinet 12. Acrankthrow 114 on the shaft 112 is connected to an end extension 116 onshaft 112 fastened against axial movement with respect to a support tab118 on the cabinet 12 by means of a snap ring 120.

A coil spring 122 is wrapped around the end extension 116 and is biaseddownwardly against a fiat 124 on the extension 116 to locate the handle110 at a point that it is readily operated by hand between tumble andno-turnble positions.

At both the tumble and no-tumble positions the flat handle is aligned inclose spaced parallelism with the front face of the door well. Thispermits a door 126- on the outer cabinet 12 to be located within thedoor well 26 to close the access opening 28. Concurrently, the door 126will close a switch 128 that is included in the energization circuit forboth the resistance element 90 and the drive motor 36.

In any position between the no-turnble and tumble positions the fiathandle 110 will prevent movement of the door 126 into the door well adistance sufficient to operate the switch 128. This assures that themanually operated controller 102 will locate the belt guard and releaseextension 108 away from belt 78 during normal operation of the drivesystem 34.

The push-pull operator 106 includes an outer elongated flexible tubularcasing 134 of wrapped wire. A pair of spaced-apart lock nuts 136 on oneend of the casing 134 fasten it to a support bracket 138 depending fromthe outer casing 12.

From this fixed point the casing 134 is bent downwardly and extendsrearwardly of and along one side of the front 16 of the outer cabinet 12until it is adjacent the base framework 40. At this point the flexiblecasing 134 is bent rearwardly until it is at a point adjacent the rearwall panel 24 and then it is bent upwardly to locate the opposite endthereof through a support tab 140 on the L-shaped bracket 46. A pair oflock nuts 142 secure the casing 134 to the tab 140.

The outer surface of the flexible casing 134 is covered by a sheath 143between its opposite ends to prevent the entrance of dust or the likethrough the coils of the casing 134. Within the casing 134 is located anelongated spring wire element or push-pull cable 144 that has one end146 thereof connected to the crankthrow 114 and the opposite end 147thereof connected to the belt guard and release extension 108.

Referring now more particularly to the belt guard and release extension108, as best seen in FIGURES 8 and 9, it includes a bent end 148 on thearm 62 that extends above and across the segment of the drive belt 78between the upper surface of the idler pulley 66 and the drive sheave 44to a point slightly outboard of the end surface on the drive sheave 44.At this point the bent end 148 is turned to form a distal end 150 on thearm 62 which is approximately perpendicular to the surface of the bentend 148. The distal end 150 has an opening 152 therethrough whichreceives the operating end 147 of the wire element 144. The operatingend 147 has a hooked portion 156 at its terminus.

To produce normal tumbling operation the operating arm 104 is located asseen in solid lines in FIGURE 2. This ushes the push-pull cable Or wireelement 144 interiorly of the casing 134 at the fixed bracket 138 andthereby forces the operating end 147 thereof into the position shown inFIGURE 3. The idler pulley 66 is held by the tension spring 58 againstthe belt reach 76 to positively couple the drive sheave 44 to the drum36 so as to cause rotation of the drum about its horizontal axis whenthe motor is energized by the controller 98. In this oper ating mode thehook 156 on the operating end 154 is located a substantial distanceabove the distal end 150. Accordingly, any slack that might develop inthe drive belt 78 is compensated by the tension spring 58 pivoting thebellcrank compensating member 54 about its fulcrum to direct the idlerpulley 66 upwardly along the arcuate path 74. The distal end 150 followsa like path and moves freely with respect to the extended operating end147.

When the manually operated controller 102 has its operating arm locatedin the no-tumble position, which is shown in dotted lines in FIGURE 2,the wire element 144 is pulled from the casing 134 at the fixed bracketend thereof so as to move the operating end 147 into a retractedposition shown in FIGURE 4 of the drawings.

In the no-tumble operating position the hook 156 on the spring wireelement is moved to engage the distal end 150 of the compensating memberarm 62 so that it will pivot about its fulcrum in a direction oppositeto that which occurs during slack compensation. This will cause theidler pulley 66 to move downwardly along the arcuate path 74 and the arm56 to move in a direction to overcome the biasing action of the tensionspring 58. When the idler pulley 66 is thereby unloaded the belt 78 nolonger will be tensioned between the drive sheave and the outerperiphery of the tumbling drum 32 and, accordingly, drum rotation isstopped.

An important feature of the present invention is that during no-tumblethe drive motor 36 is energized by the controller 98 along with theresistance element to maintain a flow of heated air through the circuitillustrated in FIGURE 5. During this type of operation the drive sheave44 will continue to rotate with respect to the untensioned belt 78. Inaccordance with certain principles of the present invention the bent end148 is configured to have a leading edge 158 thereon that is moved uponretraction of the wire element 144 downwardly and against the portion ofthe tension drive belt between the idler pulley 66 and the drive sheave44. The bent end 148 thereby serves as a belt guard, moving the beltcompletely away from the rotating drive sheave 44 during no-tumbleoperation so that there is no frictional contact therebetween that mightundesirably wear the belt during this phase of operation. The bent end148 thereby serves a dual purpose in that it will produce a firstangular movement of the bellcrank compensating member 54, to unload thedrive belt 78 thereby to decouple the motor and the tumbling drum; andin response to further retraction of the spring wire element 144 will bemoved into a physically interposed position that will shift the beltcompletely away from the drive sheave to prevent excessive wear.

One aspect of the invention is that the operating end 147 of thepush-pull spring wire element follows a path which is substantiallytangent to the arcuate path of travel of the idler pulley and thereby isfree to move between the perpendicularly arranged distal end 150 on thebent end extension 148 of the arm 62 that follows a like path.Accordingly, there is no tendency for the spring wire element to bejammed between the operating arm and the fixed casing 134 in a manner tointerfere with slack compensating movement of the idler pulley andtension spring 58.

In one working embodiment of the above-illustrated no-tumble system themotor 36 is a As horsepower motor driven at 1,750 rpm. The belt lengthand drum diameter is selected to produce a tumble speed of 49revolutions per minute and the drum capacity in one operating system is5.3 cubic feet.

At the above-described speed the blower 82 has a discharge rate ofc.f.m. The electrical resistance element, when operated at 240 volts,produces a wattage output of 4,400 watts and, when energized across 120volts, produces a wattage output of 1,100 watts.

In the operating mode the controller 98, motor, blower and resistanceelement are operated the same for both tumble and no-tumble operationand the resultant drying action differs only by the tumbling of articlesthrough the interior of the drum as effected by rotation of the drumduring tumble operation and eliminated by the improved manually operatedsystem 102 during a no-tumble phase of operation.

While the embodiment of the present invention as herein disclosedconstitutes a preferred form, it is to be understood that other formsmight be adopted.

What is claimed is:

1. In a domestic dryer the combination of a horizontal tumbling drumhaving a peripheral surface thereon, a drive motor for said drumincluding an output shaft, a drive sheave on said shaft, a continuousbelt having a portion thereof directed over said peripheral surface anda portion thereof passed over the underside of said drive sheave, anidler pulley interposed between said drive sheave and said drum, meansincluding a pivoted arm for spring biasing said idler pulley againstsaid belt during operation of said drum, said arm including an extensionoverlying said drive sheave and being located in overlying relationshipwith said single belt between said drive sheave and said idler pulley,said extension having a distal end segment, said distal end having anopening therein, a wire having an end extension directed through saiddistal end opening, a hooked end on said wire, an elongated tubularcasing for said wire, means for fixedly securing one end of said casingwith respect to said drive sheave, means for fixedly securing theopposite end of said casing, actuator means for operating said wire formoving the hooked end of said wire into a retracted and an extendedposition, said Wire in a retracted position having the hooked endthereof in engagement with said distal end of said extension forpositioning said extension in engagement with said belt between saiddrive sheave and said idler pulley to move said belt away from saiddrive sheave and thereby to disconnect said tumbling drum from saiddrive motor during a no-tumble phase of operation, said actuator meanspositioning said wire in an extended position during a tumble phase ofoperation, said hooked end of said wire being positioned out ofengagement with said distal end when in its extended position to allowfree movement of said pivoted idler pulley arm with respect to said beltthereby to maintain a slack compensating bias between said idler pulleyand said belt.

2. In a domestic dryer the combination of an outer cabinet, a tumblingdrum located within said cabinet, means for supporting said tumblingdrum within said cabinet for rotation about a horizontal axis, means fordriving said drum including a drive motor, said drive motor including anoutput shaft, a sheave connected to said output shaft, a support bracketsecured to said cabinet base, a bellcrank having its fulcrum pivotallysecured to the upper end of said support bracket, said bellcrank havingone arm thereof depending downwardly of said fulcrum} on one sidethereof, said bellcrank having a second arm thereon depending downwardlyof said fulcrum on the opposite side thereof in a direction toward saidsheave, an idler pulley supported on the lower end of said secondbellcrank, a tension spring having one end thereof connected to said onebellcrank arm, means for connecting the opposite end of said tensionspring to pivot said bellcrank about its fulcrum to cause said idlerpulley to be moved upwardly of said drive sheave, a continuously formedsingle belt wrapped around the outer periphery of said horizontaltumbling drum including a first reach extending from said drum over theupper surface of said idler pulley, said belt extending from theperiphery of said drum around the underside of said drive sheave thenceto the upper surface of said idler pulley, said idler pulley being movedby said bellcrank upwardly of said drive sheave during compensation ofslack in said drive belt along an arc to prevent the belt from beingpinched around the outer periphery of said sheave, an extension on thelower end of said second bellcrank arm extending axially of said outputshaft at a point above said drive sheave, said extension including adistal end bent with respect to said extension axially outwardly of theaxially outermost end of said drive sheave, a wire directed through saiddistal end of said extension, and actuator means connected to said wirehaving a no-tumble operating position to retract said wire at saiddistal end to pull said second arm downwardly and toward said beltbetween said idler pulley and said drive sheave and in a direction toremove the spring bias of said tension spring from said idler pulleywhereby said continuous belt is maintained slack between said drumperiphery and said drive sheave to stop drum rotation, said extensionhaving a leading edge thereon engageable with said belt between saidretracted idler pulley and said drive sheave to shift said beltdownwardly and away from said drive sheave to separate said sheave fromsaid belt when said Wire is in its retracted position thereby to preventfrictional wear of said belt by said sheave, said actuator means havinga tumble position to extend said wire at said distal end to allow freeupward movement of said extension with respect to said belt thereby tomaintain slack compensating bias between said idler pulley and saidbelt.

3. in a domestic dryer the combination of an outer cabinet having afront access pening, a door well surrounding said opening and defining arecessed space, switchmeans in said well for operating the dryer, a doorclosure pivotally supported on said cabinet for movement into said doorwell for closing said opening and to condition said switch means, atumbling drum located within said cabinet, means for supporting saidtumbling drum within said cabinet for rotation about a horizontal axis,means for driving said drumi including a drive motor supported on saidcabinet base adjacent the bottom, of said drum, said drive motorincluding an output shaft, a sheave connected to said output shaft, anupstanding support bracket secured to said cabinet base having the upperend thereof located above the center line of said output shaft and toone side of said drive sheave, a bellcrank having its fulcrum pivotallysecured to the upper end of said support bracket, said bellcrank havingone arm thereof depending downwardly of said fulcrum on one sidethereof, said bellcrank having a second arm thereon depending downwardlyof said fulcrum on the opposite side thereof in a direction toward saidsheave, an idler pulley supported on the lower end of said secondbellcrank, a tension spring having one end thereof connected to said onebellcrank arm, means for connecting the opposite end of said tensionspring to pivot said bellcrank about its fulcrum to cause said idlerpulley to be moved upwardly of said drive sheave, a continuously formedsingle belt wrapped around the outer periphery of said horizontaltumbling drum including a first reach extending from said drum, over theupper surface of said idler pulley, said belt extending from theperiphery of said drum around the underside of said drive sheave thenceto the upper surface of said idler pulley, said idler pulley being movedby said bellcrank upwardly of said drive sheave during compensation ofslack in said drive belt along an arc to prevent the belt from beingpinched around the outer periphery of said sheave, an extension on thelower end of said second bellcrank arm extending axially of said outputshaft at a point above said drive sheave, said extension including adistal end bent with respect to said extension axially outwardly of theaxially outermost end of said drive sheave, a wire connected to saiddistal end of said extension, means for directing said wire through theinterior of said cabinet to a location adjacent the door well therein,an actuator handle located I in said door well including a positionwhich precludes door closure and switch operation and a plurality ofoperating positions where the door can be closed, connecting means forfastening said wire to said actuator handle, said actuator handle havinga no-tumble operating position wherein said connecting means retractssaid wire at said distal end to pull said second arm downwardly andtoward said belt between said idler pulley and said drive sheave and ina direction to remove the spring bias of said tension spring from saididler pulley whereby said continuous belt is maintained slack betweensaid drum periphery and said drive sheave to stop drum rotation, saidextension having a leading edge thereon engageable with said beltbetween said retracted idler pulley and said drive sheave to shift saidbelt downwardly and away from said drive sheave to separate said sheavefrom said belt when said wire is in its retracted position ReferencesCited UNITED STATES PATENTS 3,429,056 2/1969 Metzger i34133 LLOYD L.KING, Primary Examiner

